1. Field of the Invention
This invention relates to an interchangeable plug valve having a valve body, an outer valve plug and an inner valve plug. A plurality of interchangeable plug valves are mounted within a parallel valve body to form a parallel porting valve assembly.
2. Description of the Prior Art
Conventional plug valves exist which essentially stop or permit fluid to flow through piping systems. Such valves have particular uses in gas and water distribution piping systems. Conventional magnetic latching valves requiring little power for activation are primarily used in remote locations where electrical power is not readily available. Many electronics manufacturers produce conventional microprocessors capable of encoding and transmitting data signals to and from such latching valves.
Little et al, U.S. Pat. No. 3,734,133 teaches a diverter pinch valve having a hollow Y-shaped resilient valve body. The '133 patent also teaches pinching means used to pinch leg portions to control flow through the Y-shaped valve body. Actuating means are used to selectively move inner and outer pinch bars to provide a gas-tight closure of one resilient leg portion, while simultaneously providing a fully opened passage within the other resilient leg portion.
Neff, U.S. Pat. No. 4,182,360 teaches a combination pressure regulating and flow control valve having an upstream port and a downstream port connected by a fluid passage. An adjustable pressure regulating valve regulates the pressure of a fluid which enters from the upstream port. A spring bias check valve, in parallel with the pressure regulating valve, allows free flow back to an upstream port if the pressure regulating valve is closed to such flow.
Ware, U.S. Pat. No. 4,513,763 discloses an inertial valve apparatus for automatically stopping fluid flow in the event of an earthquake or similar vibration, and simultaneously causing the fluid to vent. The inertial valve apparatus includes a spring-loaded double-seated valve held in an unactuated position by a latch, a suspended mass, and a trigger arm connected to the latch. A vibrating force moves the suspended mass and thus causes the latch to release and move the valve to an actuated position.
Geipel et al, U.S. Pat. No. 4,606,370 teaches a flow-switching water-mixing faucet assembly for a sanitary mixing faucet assembly or the like. A flow shifting valve stem is raised or lowered to shift a fluid flow between two outlets. The faucet assembly basically comprises an operating lever pivotally having one end connected to a valve stem and the opposite end connected to a centrally located pivot bearing.
Bernstein et al, U.S. Pat. No. 4,682,755 discloses a pinch valve mechanism having two cam members rotatably supported in a housing. Rotating the cam members transversely moves opposing shank portions both toward and away from one another. Such motion pinches a sleeve and thereby selectively throttles or stops fluid flow through a piping system.
Plug valves normally service gas and water distribution piping systems. A plug valve generally provides a gas-tight leak-free seal, which has particular importance in natural gas or other flammable fuel piping systems. The existing valves described above have several shortcomings, particularly in gas services. Once installed into the piping system, such valves cannot be easily changed or tested.